Antibody Development and Lateral Flow Assay Support for Somnus

Introduction

Somnus Scientific first approached Life Science Group (LSG) in July 2022 to develop a rabbit polyclonal antibody to propofol, with the longer-term objective of supporting development of a rapid diagnostic test. The programme subsequently progressed to mouse monoclonal antibody generation in March 2024. Four monoclonal antibodies were identified for lateral flow evaluation and the programme later included hybridoma sequencing and recombinant antibody expression.

The overall aim was to support the translation of Somnus's laboratory-based propofol immunoassay into a rapid point-of-care lateral flow test for use with clinically relevant samples. 

The Challenge: Why the Customer Came to Us

Developing an antibody is only part of the challenge. For this programme, the customer had promising reagents and evidence of antibody performance in ELISA but needed specialist support to translate that early-stage work into a robust lateral flow assay with a secure route to future reagent supply.

Propofol presented a particularly demanding target. As a small molecule, it required a competitive rather than conventional sandwich assay format, making antigen presentation and assay architecture critical to performance. Somnus needed a partner with the breadth of lateral flow development expertise to understand how antibody characteristics, conjugation chemistry, membrane behaviour and assay conditions interacted and to systematically optimise them as a complete system.

The programme also identified a potential risk to future manufacture. During scale-up of the lead GH5 hybridoma, revival of cryopreserved cells initially resulted in poor viability and inconsistent antibody production. For the customer, this created a potential dependency on an unreliable supply of a critical assay component. Addressing these required capabilities extending beyond lateral flow development into antibody production and reagent supply, with the objective of establishing a robust and reproducible route to future manufacture.

By bringing antibody expertise, conjugation chemistry and lateral flow development together within a single programme, we were able to address both the immediate assay-development challenges and the longer-term risks associated with reagent supply. For the customer, this provided a route from promising laboratory reagents towards a reproducible, scalable assay platform without having to build and coordinate these specialist capabilities internally.

Life Science Group's Role

LSG supported Somnus across the antibody and diagnostic development pathway, providing specialist antibody expertise and continuity as the programme progressed from antibody generation into diagnostic development. This support included custom polyclonal and mouse monoclonal antibody development and screening, selection of antibodies for diagnostic evaluation and development of a competitive lateral flow proof-of-concept assay in collaboration with Creonate Manufacturing and specialist conjugation partners.

To translate promising antibody performance into a viable lateral flow format, LSG and Creonate evaluated antibody conjugation to colloidal gold through antibody loading, buffer optimisations, nitrocellulose membrane comparisons incorporating novel propofol capture formats and dry-test configurations. By connecting antibody expertise with downstream assay development, the team helped address the challenges of translating antibody performance into the intended diagnostic format, progressing the programme through to testing with propofol-spiked human serum.

LSG also helped de-risk future antibody supply by maintaining the original GH5 hybridoma, sequencing the selected antibody and evaluating recombinant expression alongside conventional hybridoma-derived production. This provided Somnus with alternative routes to a critical assay reagent, supporting continuity of supply and greater flexibility for future scale-up and commercialisation.

Key Outcomes and Achievements

The programme successfully generated a panel of anti-propofol monoclonal antibodies and identified GH5 as the lead candidate for continued lateral flow development.

When the original BSA-propofol approach did not provide sufficient lateral flow performance, the team investigated alternative assay architectures. Evaluation of a biotin-propofol/poly-streptavidin capture system improved presentation of the small-molecule target and enabled further optimisation of the assay. Through iterative testing, the work progressed into a dry-test format and evaluation with propofol-spiked pooled human serum, establishing proof of concept for the competitive lateral flow approach.

The project also established an alternative route to future antibody supply through recombinant expression. ELISA comparison showed that recombinant GH5 retained strong binding to propofol and, under the conditions tested, generated higher absorbance values than the previously purified GH5 antibody across the concentrations examined.

The original hybridoma was also successfully recovered following culture optimisation, expanded and banked, providing complementary hybridoma and recombinant production routes, allowing Somnus flexibility in the routes they follow and opportunities to explore increased sensitivity.

Summary: LSG Products and Solutions

The Somnus project demonstrates LSG's ability to support a diagnostic programme from early antibody discovery through to assay feasibility and future manufacturing readiness. Services delivered across the programme included

Work completed to date has included:

• Custom rabbit polyclonal antibody development
• Mouse monoclonal antibody development and screening
• Hybridoma culture, recovery and cell banking
• Antibody sequencing
• Recombinant antibody expression
• Antibody purification and characterisation
• Colloidal-gold conjugation evaluation
• Lateral flow feasibility and optimisation support.
• Supply of propofol-positive human serum and blood samples

The collaboration provides Somnus with both a lead anti-propofol antibody and a development pathway towards a sequence-defined, reproducible antibody supply for continued point-of-care test development. Somnus is now focused on further optimisation of the lateral flow format and progression towards increasingly representative prototypes and clinical evaluation.

Email sales@lifesciencegroup.co.uk to discuss your requirements.